1. Clicker #1
How many of the following statements are true?
I. All atoms of the same element are identical.
II. Negatively charged particles are embedded in a positively charged cloud throughout the atom.
III. As verified by Rutherford, only positively charged particles called protons are found inside the nucleus.
IV. J.J. Thomson provided the first experimental support for the atom.
A) B) 1 C) 2 D) E) 4

2. White Light Why is white light white? Energy:
Related to the wavelength of light (also relates to the colors of light)
Travels through space (Electromagnetic Radiation- contains visible light)

3. Electromagnetic Spectrum
Increasing Wavelength
Increasing Energy

4. (resistance through a wire)
Example: Light Bulb
Energy as
Light and Heat
Heating Wire
(resistance through a wire)

5. Clicker #2
Why does the pickle (the system) give off light? Choose the best answer.
A) If you run electricity through anything, it will give off light.
B) When protons are in an excited state due to electricity, they glow.
C) The pickle contains sodium. The electricity is causing the neutrons inside sodium to move across between the two forks and thus make it glow.
D) Energy was put into the pickle (by electricity) so it’s returning back to a lower energy state by releasing light.

6. What puts atoms in an excited state?
Applied Energy!
Electrons MOVE AROUND
Electrons
Like to be near nucleus
Need energy forces to keep them away
Energy released when electrons fall back toward nucleus
Colored light!!!

7. Energy Levels Only certain energy levels are allowed DEMO: Flame Tests
Different colors = Different Ions
NONE are white light
ENERGY is NOT a continuous spectrum
ENERGY is DISCRETE spectrum

8. “Quantized” Energy Levels
Time travel
..VERSUS..
Quantum Leap

9. “Quantized” Energy Levels
Energy emitted/absorbed from an atom in discrete packets
Electrons excited or released toward ground state to specific energy levels

10. Niels Bohr Model

11. Niels Bohr Model
WRONG!!!!

12. Niels Bohr Model Good at explaining energy levels
Electrons go from one energy level to another
Electrons can ONLY exist at certain energy levels
Works well mathematically for Hydrogen, but not for other elements

13. Clicker #3 When an electron is excited in an atom or ion
A) the electron moves further from the nucleus.
B) only specific quantities of energy are released in order for the electron to return to its ground state.
C) white light is never observed when the electron returns to its ground state.
D) the electron is only excited to certain energy levels.
E) All of the above statements are true when an electron is excited.

14. “Waves” and “Particles”
An electron can behave like a particle
An electron can behaves like a wave
(every electron has a wavelength associated with it)
Louis Victor de Broglie and Erwin Schrödinger

15. Wave Properties QUANTIZED ENERGY!!!!!!!! Can cancel and add up
The more energy they have the more complicated the wave gets
Waves are associated with probability
If a wave cancels (i.e.- wavelength = 0) then there is zero probability you will find an electron there
QUANTIZED ENERGY!!!!!!!!

16. Think of electrons in terms of probabilities!
Firefly example